"His philosophy is often divided into an early period, exemplified by the Tractatus, and a later period, articulated primarily in the Philosophical Investigations. The "Early Wittgenstein" was concerned with the logical relationship between propositions and the world and he believed that by providing an account of the logic underlying this relationship, he had solved all philosophical problems. The "Later Wittgenstein", however, rejected many of the assumptions of the Tractatus, arguing that the meaning of words is best understood as their use within a given language-game."